An electronic device, such as an OLED display, is used in applications such as a display of a cellular phone because the electronic device is thin, is excellent in displaying a moving image, and has low power consumption.
A glass substrate is widely used as a substrate of an OLED display. An alkali-free glass (glass in which the content of an alkali component is 0.5 mol % or less in a glass composition) is used for the glass substrate of this application. With this, a situation in which an alkali ion is diffused in a heat treatment step into a semiconductor substance having been formed into a film can be prevented.